Antimicrobial Preservatives and Additives – Aldehydes

Formaldehyde is the most basic form of aldehyde representing the class of reactive antimicrobials.

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Formaldehyde and aldehydes can be volatile at room temperature leading to the odor commonly associated with preservation of tissue or tissue samples such as in laboratories, hospitals, and mortuaries.

As a class of antimicrobials, formaldehydes are known as reactive antimicrobials, in that their predominant mechanism of action for controlling microorganisms is to react with peptides and proteins. As this reaction progresses throughout an organisms its biochemical processes become increasingly impaired and the organism dies. This mechanism makes aldehyde types of chemistries very potent for all types of microorganisms such as bacteria, fungi, algae and viruses. It also makes this type of chemistry problematic for use around human tissue. Very selective and stringent guidelines must be followed to manage the appropriate use of aldehyde chemistries.

Given the efficacy and utility of these types of chemistry, manufacturers of aldehyde based antimicrobials have undertaken strategies to produce larger compounds, that when in the presence of water, will break apart (hydrolyze) and release monomers of formaldehyde or aldehyde containing groups. These molecules can then provide the antimicrobial actions needed but avoiding some of the health, safety and stability issues with formulating the formaldehyde molecule.

Antimicrobial Uses

Due to its tremendous versatility and broad spectrum efficacy as an antibacterial, antifungal, antiviral, sporicide, antialgal, and protozoacide, even against macro-organisms such as mollusks and other invasive species. Aldehyde chemistries are one of the most broadly used in industry. These chemistries are used as medically registered high level disinfectants, used in animal bio-security for maintenance and to control of viral outbreaks, and as preservatives for cosmetics and personal care products. Because of their reactivity and cost effectiveness, aldehyde chemistries are used in many applications alone or in combination with other types of preservatives that would use different mechanisms for controling the microorganism contaminats. A common technique in antimicrobial formulation development is combining a fast acting antimicrobial with a different type of slower performing chemistry.

As industry has become more aware of potential issues with the use of some aldehyde chemistries, their applications and use patterns have changed. But don’t confuse formaldehyde with aldehyde containing chemistries, in terms of their toxicity and safety. Hundreds of aldehyde chemistries have been in use for other applications such as polymers (thermoset resins) and catalyst in industry, to permanent press textile coatings for consumer products, is a good indication of their overall utility. As awareness has grown about the potential issues with formaldehyde the EPA and other regulatory agencies have developed more stringent handling practices to address the potential dangers associated with high concentrations of formaldehyde.

In considering the type of microbial additive used, it is always a good idea to review the handeling needs of one chemistry over others so that the solution is optimized for the given antimicrobial application.